Experimental determination of the hysteretic behaviour of soil-water retention curve of silty sands

Shear behaviour of unsaturated silty sands is closely linked to the soil-water retention curve (SWRC). The SWRC depends beside the pore structure mainly on the hydraulic path. It hence shows hysteretic behaviour for wetting and drying cycles. This paper presents the results of the experimental determination of the boundary drying and wetting curve for two silty sands. The measurements were carried out using tensiometers at low suctions and the dew point method at high suctions. The influence of water content during compaction was studied by measuring the boundary drying and wetting curves for one silty sand compacted at two different water contents. The experimental results were compared to the predictions of 3 empirical models. The study showed that all models compare well to the experimental results for water contents above the residual water content. A modification was suggested to improve the performance at low water contents